Electroless Nickel Thickness Vs. Salt Fog Resistance

.

We are looking to plate steel parts with
Mil-C-26074 [link by ed. to spec at TechStreet] electroless nickel. Since the parts are steel, it is recommended that the Grade Coating be applied (0.0015-inch thick). We can only go up to 0.0008 inch, max. due to insertion requirements for the finished product. The question is: What kind of salt fog ( ASTM B117 [link by ed. to spec at TechStreet]
) resistance can we expect to get from coating a steel part with 0.0008-inch of electroless nickel? Can we achieve 48-hours? 200-hours? What about for 0.0005-inch (Grade B)?

There are a lot of factors that effect the corrosion resistance,but the factors that have the greatest effect are surface roughness and%P of the EN. The lower the surface roughness the better the corrosion resistance. Also the higher the %P the better the corrosion resistance.

You should be able to get 48 hrs of salt spray from a high P EN deposit.

George Shahin- Rock Hill, South Carolina

.

George is right, roughness, P content have a great effect on SS resistance but on top of that, heating which is done to improve hardness has also a great effect. For instance, 25 microns of high PEN should result in about 1000 hours in SS but if you heat it , the resistance will be reduced to about 100 hours.